Aspas was strongly linked with a move to England in January, with Reading and Swansea reported to be the main suitors.
Reports in Spain have since claimed that Tottenham have a strong interest in the 25-year-old.
A fee of £5million has been suggested, but Celta insist that they will not allow Aspas to leave for less than his €10million (£8.3million) clause.
A Celta source told Sky Sports: "Celta have cleared this subject with the player and his agent. Iago is our main player and it is only possible he will leave for a just price.
"Things have not changed, his clause is set and we will not accept any negotiation on this."